Title page for ETD etd-11122009-184612

Atomistic Simulations of Lipid Bilayers in the Presence of Dimethylsulfoxide

Degree

Master of Science in Mechanical Engineering (M.S.M.E.)

Department

Mechanical Engineering

Advisory Committee

Advisor Name

Title

Devireddy, Ram V.

Committee Chair

Moldovan, Dorel

Committee Co-Chair

Nikitopoulos, Dimitris E.

Committee Member

Keywords

DMSO

Lipids

Molecular Dynamics

Simulations

Gromacs

Date of Defense

2009-11-04

Availability

unrestricted

Abstract

In a typical cryopreservation protocol, the system to be preserved is first equilibrated with chemicals known as cryoprotective agents (CPAs). CPAs have been shown to alleviate cell damage from either the solute effects or the formation of intracellular ice during the subsequent freezing process. Thus, an extensive body of literature reporting the effects of CPAs on cellular systems has been accumulated over the last 50 years; detailing largely experimental interactions between cell systems and chemicals. Recent advances in computational methodology now offer an additional dimension in our ability to understand the molecular interactions between cell membranes, idealized as lipid bilayers and CPAs at atomistic scales. Computer simulations provide unique capabilities for analyzing biomembrane properties from atomistic perspective with a degree of detail that is hard to reach by other techniques. Molecular Dynamic (MD) simulations have been performed on phospholipid bilayers composed of Dimyristoylphosphatidylcholine (DMPC) lipids. The focus of our MD simulations was on the development of a fundamental understanding of the effects of low and moderate concentrations of dimethylsulfoxide (DMSO) on lipid bilayers membranes when exposed symmetrically or asymetrically to the water-DMSO solution. The molecular dynamic investigations show that the increase in concentration of DMSO leads to increase in area per lipid which in turn decreases the thickness of the bilayer. Moreover, the DMSO also has a significant effect on several other structural properties such as ordering of lipid tails and dipolar orientation ordering of the water molecules located near the water-bilayer interface.